1. Field of the Invention
The invention relates in general to a method for generating a gamma table, and more particularly to a method for generating a gamma table by calculating and recording gamma reference values with a lower bit number from the known corrected gray levels.
2. Description of the Related Art
The liquid crystal display (LCD), due to advantages of small volume, low weight and low electromagnetic radiation, has been widely used in these few years. However, owing that the voltage drop across two sides of liquid crystal molecules is not linearly proportional to the light transmittance, when the digital image data to be displayed is converted into the voltage signals to the two sides of the liquid crystal molecules, a gamma correction operation has to be performed in order to reduce color distortion of the LCD.
Normally, the gamma correction operation is performed to generate corrected gray levels from the original gray levels of pixels via mapping according to a gamma curve. The gamma curve is a gamma table recorded in a relevant circuit of the display. When the LCD has to perform the gamma correction operation, the required corrected gray levels corresponding to the original gray levels can be obtained according to the recorded gamma table.
In the gamma correction of the LCD, for example, 10 bits of corrected gray levels y are generated from 8 bits of original gray levels x, wherein x=0˜255, y=0˜1023, y=(x/255)γ×1023, and γ is a gamma coefficient. Supposed that compression or correction is not performed, the memory space required by the LCD is 258×10=2580 bits. Owing to the large memory space, the LCD has a lower speed of gamma correction and a higher manufacturing cost.